Side Space

Side Space is a browser extension that brings an Arc-style vertical tab sidebar to Chrome, Firefox, and other Chromium-based browsers. It combines tab management with an AI assistant called Side Copilot that can organize, summarize, research, and automate browsing tasks directly from the side panel. Originally launched as a tab organizer in 2024, Side Space has evolved into a full-featured browser companion with over 16,000 users.

What Side Space Does

Side Space replaces the crowded horizontal tab bar with a clean vertical sidebar. You can group tabs into named Spaces for different contexts like work, study, research, or shopping. Each Space can be named, themed with custom colors, and synced across devices through cloud sync. The extension supports drag-and-drop reordering, tab pinning, and saving and restoring tab groups.

The AI Copilot is the standout feature. In Chat Mode, it can summarize the current page, answer questions about open tabs, and compare content across pages. In Agent Mode, the AI takes action directly in the browser, such as grouping tabs by topic, managing windows, searching browsing history, and automating repetitive workflows. The AI can also group tabs automatically using natural-language prompts or custom categories.

Key Features

• Vertical tabs sidebar with a clean, Arc-like layout that is easier to scan than the default horizontal bar.
• Spaces for organizing tabs into separate workspaces, each with its own color theme and settings.
• AI Copilot Chat Mode for summarizing pages, explaining content, and answering questions about your browsing context.
• AI Copilot Agent Mode for automating browser actions like grouping tabs, managing windows, and searching history.
• Cross-browser cloud sync for keeping Spaces available across Chrome, Edge, Brave, Vivaldi, Firefox, and other browsers.
• Fuzzy search to quickly find any open tab or Space by name.
• Tab suspension to free up memory by suspending inactive tabs.
• Auto-grouping with Group Guard that detects and groups tabs by domain patterns or custom rules.
• Dark mode, multi-language support (5 languages), and customization options.
• Save and restore tab sessions with JSON backup export.

Pricing

Side Space offers a free tier with up to 5 Spaces and access to the AI Copilot Chat Mode. The Pro plan at $2.99 per month unlocks unlimited Spaces, Agent Mode, BYOK for custom AI models, and premium shortcuts. The Pro+ plan at $7.99 per month adds cross-page agent capabilities, AI chat history sync, YouTube video chat, PDF and document chat, mind map generation, and access to beta features. A lifetime license is available for $79.00.

Who It Fits

Side Space is useful for heavy tab users who want a cleaner browsing experience without switching to a specialized browser like Arc or Dia. It suits researchers managing dozens of reference tabs, developers keeping multiple documentation pages open, students organizing course materials, and anyone who finds Chrome's default tab bar difficult to manage. The AI features make it especially valuable for users who want to summarize, organize, or take action on their browsing context without manually sorting through every tab.